Muzzle bushing assembly for power-actuated fastening tools

ABSTRACT

An adjustable muzzle bushing assembly for a powder-actuated tool having means to prevent the muzzle bushing thereof from accidentally moving out of adjustment. The assembly includes a collet with a threaded bore which receives an externally threaded muzzle bushing. A longitudinal portion of the external surface of the muzzle bushing is reduced and the collet has a portion of its external surface reduced to form a flat surface intersecting its bore. A spring has a portion coiled about the collet and a straight portion in engagement with the flat surface and the muzzle bushing to act as a detent when the spring is in engagement with the flat surface of the muzzle bushing.

United States Patent 51 July 11,1972

Bakoledis [54] MUZZLE BUSHING ASSEMBLY FOR POWER-ACTUATED FASTENINGTOOLS [72] Inventor: Andrew G. Bakoledis, Clinton, Conn.

[73] Assignee: Olin Corporation [22] Filed: Mareh8, 1971 [21] Appl.No.:121,635

[52] U.S.Cl ..227/8,227/l0 [5i] lnLCl. ..B25cl/l4 [58] FieldofSear-ch..227/8,9,l0,ll

[56] References Cited UNITED STATES PATENT 2,925,603 2/1960 Pfaffetal...2 27/8 3,468,466 9/1969 Wackrow ..227/l0 3,534,895 10/1970 Henning..227/l0 3,575,332 4/1971 Brunelle ..227/l0 Printary Examiner-GranvilleY. Custer, Jr. Attorney-Donald R. Motsko, H. Samuel Kieser and WilliamW. Jones [57] ABSTRACT face and the muzzle bushing to act as a detentwhen the spring is in engagement with the flat surface of the muzzlebushing.

7 Claim, 4 Drawing Figures MUZZLE BUSHING ASSEMBLY FOR POWER- ACTUATEDFASTENING TOOLS This invention relates generally to powder-actuatedfastening tools. More particularly, the invention relates to such toolshaving an improved muzzle bushing assembly.

There are certain powder-actuated fastening tools on the market whichare fired by moving the body of the tool toward the work surface. Thesetools are so designed that the fastener will hold the piston memberstationary when the body of the tool moves to cause ignition of thepowder charge. These tools are usually equipped with an adjustablemuzzle bushing for holding the fastener. The muzzle bushing usuallycomprises a member threaded into a nut so that the muzzle bushing can berotated to cause increased or decreased extension of the muzzle bushingfrom the end of the body of the tool.

The purpose of providing the adjustable feature is so fasteners ofvarying lengths can be used with the same tool. However, it has beenfound that in some cases, due to vibration and other forces, a muzzlebushing will tend to come out of adjustment with the possible resultthat either the-fastener will not be properly guided or the powderCharge will not be ignited.

In view of the above, it is an object of the present invention toprovide a powder-actuated fastening tool having an improved muzzlebushing assembly.

More particularly, it is an object of the present invention to provide afastening tool having a muzzle bushing assembly which helps to insureproper adjustment of the muzzle bushmg.

More specifically, another object of the present invention is theprovision of a muzzle bushing assembly for a powder-actuated toolwherein a muule bushing which adjusts by threading will be retained inits proper adjusted position.

These and other objects and advantages of the present invention willbecome more apparent by reference to the following description of apreferred embodiment of the invention and to the accompanying drawingsin which:

FIG. 1 is a cross sectional view of a tool incorporating the improvedmuzzle bushing assembly of the present invention;

FIG. 2 is an enlarged partial sectional view of the forward or muzzleend of the tool of FIG. 1;

FIG. 3 is a transverse sectional view taken along the lines 3-3 of FIG.2; and

FIG. 4 is a sectional view taken in the direction of lines 4-4 in FIG.2.

An example of the tool in which the improved muzzle bushing assembly ofthe present invention may be used is shown in FIG. 1. Generally, thetool comprises a housing assembly 2, a barrel assembly 4 attached to thehousing assembly 2, the improved muzzle bushing assembly 6 operablyconnected to the barrel assembly 4 for relative movement therewith, anda piston assembly 8 mounted within the barrel assembly 4 for relativemovement therewith.

The housing assembly 2 includes a block-like housing member 10 theforward end of which is provided with an internally threaded counterbore12. A second counterbore 14 is provided having an axis extending in adirection perpendicular to the axis of the tool. The counterbore 14extends a portion of the way through the housing member 10 to a shoulder16 with a reduced bore 18 extending the remainder of the way. Theforwardmost surface of the counterbore 14 is spaced rearwardly from thebottom of the counterbore 12 to provide a breech face 20. The breechface 20 is provided with a port 22 having an axis coincident with theaxis of the barrel assembly 4.

A powder charge receiving drum 24 is rotatably mounted within thecounterbore l4 and reduced bore 18 in the housing member 10. The drum 24is provided with a first cylindrical outer surface 26 which is in tight,but rotatable engagement with the surface of the counterbore 14, abottom shoulder 28 which engages the shoulder 16 formed by thecounterbore l4, and a reduced, cylindrical portion 30 having a surfacein engagement with the reduced bore 18. The end of the reduced,

cylindrical portion 30 projects beyond the housing.

The top surface 32 of the powder charge receiving drum 24 is flat. Aplug 34 having a flat bottom surface 38 and external threads is threadedinto the threaded upper portion 36 of the counterbore so that its bottomsurface 38 is in contact with the top surface 32 of the drum 24 toconfine the drum 24 between the plug 34 and the shoulder 16 formed bythe counter-bore 14, thereby preventing lateral movement. Thecylindrical surface 26 of the drum 24 is provided with a powder chargereceiving chamber 40. In the particular tool shown, the powder chargereceiving chamber 40 is of the type adapted to receive a pellet ofcaseless ammunition. When the tool is in the firing position as shown inFIG. 1, the powder charge receiving chamber 40 is in alignment with theport 22 in the breech face 20. A handle 42 is attached to the drum 24 torotate the drum 24 180 into its loading position wherein the powdercharge receiving chamber 40 is in communication with a loading port 42in the rearward face of the housing 2.

The barrel assembly 4 includes a barrel member 44 having an externallythreaded rearward end 46 which is threadedly secured within the threadedcounterbore 12 in the housing 2. The main cylindrical bore 48 of thebarrel member 44 extends from the forward end thereof to ataperedshoulder 50 which tapers inwardly and rearwardly until it meets with areduced, cylindrical bore 52 which extends to the rearward end of thebarrel member 44. The outer surface 54 of the barrel member 44 isreduced adjacent its forward end to form a shoulder 56. The outersurface 58 immediately rearward of the shoulder 56 is externallythreaded and is connected to an internally threaded cap member 60. Thecap member 60 has a generally cylindrical internal surface 62 with itsforward end having an internal stop shoulder 66. A grip 68 of rubber,plastic or other suitable material, surrounds the barrel member 44 andextends from the rearward face 70 of the cap member 60 to the forwardface 72 of the housing member 10.

The improved muzzle bushing assembly 6 includes a collet 74 mountedwithin the cap member 60 and having an internally threaded bore 75. Thecollet 74 includes an outwardly extending flange 76 intermediate itsends providing the collet 74 with a reduced forward portion 78 and areduced rearward portion 80. The flange 76 provides the collet 74 with aforward abutment surface 82 and a rearward surface 84. A muzzle bushing86 having a bore 88 extending therethrough is externally threadedthrough its length except for a small portion adjacent the forward andrearward ends thereof. The threads 90 on the muzzle bushing 86 areinterrupted by two reduced diametrically opposed areas extendingthroughout the length of the threads 90 to provide two opposedlongitudinally extending flat surfaces 92 and 94 on the outside surface.The muzzle bushing 86 is threadedly received within the threaded bore 75of the collet 74.

The reduced rearward portion 80 of the collet 74 has a portion of itsside wall cut away as shown in FIGS. 3 and 4 to form a flat planarportion 96 which interrupts the bore 75 so that the flat planar portion96 will be substantially coplanar with one of the flat areas 92 and 94on the muzzle bushing 86 when those components are in the position shownin FIG. 3. The rearward reduced portion 80 is also provided with acircumferentially extending groove 98. A compression spring 100, havingits forwardmost coil 102 reduced and its forward end portion formed intoa straight section 104, is snapped into the groove 98 on the collet 74with the straight section'104 of the spring laying against the flatportion 96 as shown in FIG. 3. The other end 106 of the spring abutsagainst the shoulder 56 on the barrel member 44. The spring 100 acts intorsion to prevent accidental turning of the muzzle bushing 86 relativeto collet 74 as will be described in more detail below, as well as actsto bias the collet into a position wherein its forwardmost abutmentsurface 82 abuts the stop shoulder 66 of the cap member 60.

The piston assembly 8 includes a piston member 108 having a head portion1 10 mounted within the barrel member 44 and outer edge of the a reducedram portion 112 extending forwardly into the muzzle bushing 86. Thepiston head 110 includes an outwardly extending flange 114 to provide ashoulder 116 against which one end of a coil spring 118 abuts. The otherend of the coil spring 118 abuts the shoulder 50 in the barrel member44. Projecting axially from the rearwardmost end of the piston member108 is a firing pin projection 120. The spring 118 serves to insure thatthe firing pin projection 120 of the piston member 108 will not projectinto the powder charge receiving chamber 40 after the tool is beingfired.

Prior to the firing operation, the operator should adjust the muzzlebushing for the particular length fastener to be used. To do this, thehandle 42 is rotated so as to move the powder charge receiving chamber40 out of alignment with the port 22 and the firing pin projection 120.A fastener 122 is then inserted in the forward end of the muzzle bushing86 and pushed rearwardly until it engages the piston member 108. Themuzzle bushing 86 is then rotated in the proper direction with respectto the collet 74 so that the muzzle bushing 86 will be moved axially toa point where it is substantially flush with the tip of the fastener122. The straight section 104 of the spring 100 applies pressure throughtorsion to the flat areas 92 or 94 on the muzzle bushing 86. The spring100 has sufficient give so that the threads 90 of the muzzle bushing 86will cam the straight section 104 off one fiat area onto the other oneupon 180 rotation when desired. However, when the muzzle bushing 86 isproperly adjusted, the straight section 104 of the spring 100 will be inengagement with a flat area 92 or 94 of the muzzle bushing 86 and due totorsion, apply a sufficient force to the fiat area so that the muzzlebushing 86 will be prevented from accidentally turning and therebybecoming improperly adjusted. To aid in rotating the muzzle bushing 86for adjustment purposes, the forward end of the muzzle bushing 86 isprovided with a transverse bore 124. The collet 74 has a transverse bore126 which is adapted to align with a transverse bore 128 in the capmember 60. A fastener may be inserted into the bores 126 and 128 to holdthe collet 74 stationary while a fastener may be inserted into the bore124 in the muzzle bushing 86 whereby additional leverage may be obtainedto rotate the muzzle bushing 86 relative to the collet 74.

With a powder charge in the powder charge receiving chamber 40, and thechamber 40 in line with the port 22, the tool may be fired by placingthe forward end of the muzzle bushing 86 against the work surface andapplying a sharp blow to the rearward end of the housing member by asuitable instrument such as a hammer or the like. The housing assembly 2and barrel assembly 4 will move forward relative to the muzzle bushingassembly 6 and piston assembly 8 so that the firing pin projection 120will project into the powder charge receiving chamber 40 and cause theignition of the powder charge. The spring 100, being under compression,will return the collet 74 forward until it abuts the shoulder 66 of thecap member 60 after the tool is fired.

What is claimed is:

1. An adjustable muzzle bushing assembly for use in a powder-actuatedtool, said assembly comprising a collet member having a threaded boretherethrough, a muzzle bushing having a bore therethrough and anexternally threaded surface throughout at least a portion of its lengthand being threadedly received in the bore of the collet member, theexternal surface of said muzzle bushing having at least one1ongitudinally extending reduced portion interrupting said threads, saidcollet member having a portion of its external surface reduced to form aflat surface extending parallel to the axis of its bore and intersectingsaid bore, a spring having a portion circumferentially coiled about aportion of the external surface of said collet member and a straightportion in engagement with said flat surface of said collet member andsaid muzzle bushing.

2. The muzzle bushing assembly of claim 1 wherein there are twodiametrically opposed reduced flat surfaces on the external surface ofsaid muzzle bushing interrupting said threads. The muzzle bushing ofclaim 1 wherein said collet member includes an outwardly extendingflange and a reduced rearward portion, said reduced rearward portionhaving a portion of its external surface reduced to form the flatsurface extending parallel to the axis of its bore and intersecting saidbore, a circumferentially extending groove in the remainder of thereduced section, said spring having its coiled portion received withinsaid groove.

4. In a powder-actuated tool, barrel means, a muzzle bushing assemblyconnected to said barrel means and having a portion extending from theforward end thereof, said muzzle bushing assembly having relative axialmovement with respect to said barrel means, stop means for limitingforward movement of said muzzle bushing assembly with respect to saidbarrel means, said muzzle bushing assembly comprising a collet memberhaving a threaded bore therethrough and an externally threaded surfacethroughout at least a portion of its length and being threadedlyreceived in the bore of said collet member, the external surface of saidmuzzle bushing having at least one longitudinally extending reducedportion interrupting said threads, said collet member having a portionof its external surface reduced to form a flat surface extendingparallel to the axis of its bore and intersecting said bore, a springhaving a portion circumferentially coiled about a portion of theexternal surface of said collet member and a straight end portion inengagement with said said flat surface and said muzzle bushing.

5. In the powder-actuated tool of claim 4, said muule bushing having twodiametrically opposed reduced flat surfaces interrupting said threads.

6. In the powder-actuated tool of claim 4, said barrel means having ashoulder therein spaced rearwardly from said collet member, said colletmember including an outwardly extending flange and a reduced rearwardportion having the flat surface therein, said spring having its portioncoiled about said reduced portion and its straight portion engaging theflat surface in the reduced portion of the collet member, said springbeing a coil spring with its other end in engagement with said shoulderin said barrel means to provide the means biasing said barrel assembly.

7. In a powder-actuated tool, a housing; barrel means attached to saidhousing; a muzzle bushing assembly operably connected to said barrelmeans and having a portion extending from the forward muzzle endthereof, said muzzle bushing assembly having relative axial movementwith respect to said barrel; stop means for limiting forward movement ofsaid muzzle bushing assembly with respect to said barrel means; saidmuzzle bushing assembly including a collet member mounted within saidbarrel means, said collet member having a threaded bore therethrough, amuzzle bushing having a bore therethrough and having at least a portionof its length threaded and threadedly received within the bore of saidcollet member, the external surface of said muzzle bushing having atleast one longitudinally extending reduced portion interrupting saidthreads, said collet member having a portion of its surface reduced toform a flat surface extending parallel to the axis of its bore andintersecting its bore, a coil spring having a portion of a coil loopedabout a portion of the circumference of said coil and a straight portionin engagement with said flat surface and in engagement with said muzzlebushing; piston means having a driving portion extending into saidmuzzle bushing; a powder charge receiving chamber; a firing pin; one ofsaid powder charge receiving chamber being moveable with said pistonmeans and the other being stationary with respect to said housing duringthe firing of said tool.

1. An adjustable muzzle bushing assembly for use in a powderactuatedtool, said assembly comprising a collet member having a threaded boretherethrough, a muzzle bushing having a bore therethrough and anexternally threaded surface throughout at least a portion of its lengthand being threadedly received in the bore of the collet member, theexternal surface of said muzzle bushing having at least onelongitudinally extending reduced portion interrupting said threads, saidcollet member having a portion of its external surface reduced to form aflat surface extending parallel to the axis of its bore and intersectingsaid bore, a spring having a portion circumferentially coiled about aportion of the external surface of said collet member and a straightportion in engagement with said flat surface of said collet member andsaid muzzle bushing.
 2. The muzzle bushing assembly of claim 1 whereinthere are two diametrically opposed reduced flat surfaces on theexternal surface of said muzzle bushing interrupting said threads. 3.The muzzle bushing of claim 1 wherein said collet member includes anoutwardly extending flange and a reduced rearward portion, said reducedrearward portion having a portion of its external surface reduced toform the flat surface extending parallel to the axis of its bore andintersecting said bore, a circumferentially extending groove in theremainder of the reduced section, said spring having its coiled portionreceived within said groove.
 4. In a powder-actuated tool, barrel means,a muzzle bushing assembly connected to said barrel means and having aportion extending from the forward end thereof, said muzzle bushingassembly having relative axial movement with respect to said barrelmeans, stop means for limiting forward movement of said muzzle bushingassembly with respect to said barrel means, said muzzle bushing assemblycomprising a collet member having a threaded bore therethrough and anexternally threaded surface throughout at least a portion of its lengthand being threadedly received in the bore of said collet member, theexternal surface of said muzzle bushing having at least onelongitudinally extending reduced portion interrupting said threads, saidcollet member having a portion of its external surface reduced to form aflat surface extending parallel to the axis of its bore and intersectingsaid bore, a spring having a portion circumferentially coiled about aportion of the external surface of said collet member and a straight endportion in engagement with said said flat surface and said muzzlebushing.
 5. In the powder-actuated tool of claim 4, said muzzle bushinghaving two diametrically opposed reduced flat surfaces interrupting saidthreads.
 6. In the powder-actuated tool of claim 4, said barrel meanshaving a shoulder therein spaced rearwardly from said collet member,said collet member including an outwardly extending flange and a reducedrearward portion having the flat surface therein, said spring having itsportion coiled about said reduced portion and its straight portionengaging the flat surface in the reduced portion of the collet member,said spring being a coil spring with its other end in engagement withsaid shoulder in said barrel means to provide the means biasing saidbarrel assembly.
 7. In a powder-actuated tool, a housing; barrel meansattAched to said housing; a muzzle bushing assembly operably connectedto said barrel means and having a portion extending from the forwardmuzzle end thereof, said muzzle bushing assembly having relative axialmovement with respect to said barrel; stop means for limiting forwardmovement of said muzzle bushing assembly with respect to said barrelmeans; said muzzle bushing assembly including a collet member mountedwithin said barrel means, said collet member having a threaded boretherethrough, a muzzle bushing having a bore therethrough and having atleast a portion of its length threaded and threadedly received withinthe bore of said collet member, the external surface of said muzzlebushing having at least one longitudinally extending reduced portioninterrupting said threads, said collet member having a portion of itssurface reduced to form a flat surface extending parallel to the axis ofits bore and intersecting its bore, a coil spring having a portion of acoil looped about a portion of the circumference of said coil and astraight portion in engagement with said flat surface and in engagementwith said muzzle bushing; piston means having a driving portionextending into said muzzle bushing; a powder charge receiving chamber; afiring pin; one of said powder charge receiving chamber being moveablewith said piston means and the other being stationary with respect tosaid housing during the firing of said tool.